Refrigerating apparatus



A. A. KUCHER ETAL 2,354,865

REFRIGERATING APPARATUS Aug. 1, 1944.

'7, 1941- 2 Sheets-Sheet 1 .za

Filed Jan. 1 42 INVENTOR. Avon-MA. 41mm: Aux flJlf tognaek BY Ana 670mm.Ml-ttf'r.

Aug. 1, 1944.

A, A. KUCHER ETAL REFRIGERATING APPARATUS I Filed Jan. 17, 1941 2Sheets-Sheet 2 INVENTORS. L lull. fir'amuu 440 624mm. W. k arr. 7

ldlklhf A new Patented Aug. 1,1944

OFFICE REFRIGERATIN G APPARATUS Andrew A. Kncher, Oakwood, and Alex A.Mc-

Cormack and Glenn W. Wolcott, Dayton,

Motors Corporation, Day- Ohio; a corporation of Delaware assignors toGeneral ton,

Ohio,

Application January 17, 1941, Serial No. 374,908 2 Claims. 01. 257-140)This invention relates to heat exchangers and particularly heatexchangers formed of sheet metal plates.

- An object of our invention isto provide an improved heat exchangerconstructed substantially in its entirety of thin gauge sheet metalplates arranged in secured together pairs to form a compact structurehaving a maximum of heat transfer surfaces by rendering all portions ofthe plates except small abutting portions thereof direct'heat flow pathsbetween a fluid within the structure and a medium exteriorly thereof.

Another object of our invention is to provide a heat exchanger of thetype wherein a plurality of thin metal plates are fabricated in such amanner that when secured together in pairs to provide a closedfluidpassageway between the groups of plates the 'walls of thepassageways are of an improved form or contour which will withstand highpressure.

Another object of ourinvention is to form a heat exchanger from aplurality of thin metal plates secured together in pairs which platesare prefabricated with dimple-like depressions including fiat portionsand intermediate connecting portions and wherein all theflat portions.of the plates are in abutting relationand thespaced apart intermediateportions of the plates provide continuously curved or arcuate wallsurfaces of fluid passageways between the plates of the pairs thereoffor increasing the strength of the walls of the'passageways.

A further object of our invention is provide a condenser for arefrigerating system by abutting portions of thin metal plates of pairsthereof having refrigerant passageways therebetween and securing wallparts of apertures in one plate of one pair thereof to wall parts ofapertures in a plate of anotherpair to form spaced headers extendingalong the length of the condenser, and wherein the secured togetherwalls of the apertures mayform the sole means forlocking the pairs ofplates together and for holding the abutting portions of the plates ofthe various pairs against one another.

,A still further object of our invention is to provide a heat exchangeror condenser of the .7

typeset forth in the preceding objects wherein the sheet metal plates ofeach pair thereof are provided with dimple-like depressions oversubstantially theirentire area andwherei-n'the depressions includespaced apart flat portions and with opposed convex wall surfaces forincreasing I the strength thereof to withstand high-internal pressure.

Further objects and advantages reside in the 1 cooperation of parts ofthe structure which facilitate the manufacture and assembly ofourimproved exchanger and inthe novel combination and arrangement toprovide a strong efficient unit of low manufacturing costs as will morefully appear in the course of the following description. V

In the drawings:

Fig. 1 is a diagrammatic showing of a refrigerating system having acondenser constructed in accordance with the present invention therein;Fig. 2 is an enlarged fragmentary front view partly in section andpartly in elevation of the pairs of plates forming thecondenser shown inFi 1; h

Fig.3 is an end view of the condenser shown in Fig. 2;

Fig. 4 is an enlarged fragmentary view taken on the line 4-4 of Fig. 2showing a portion of the face of a plate of one of the pairs thereof inthe condenser;

Fig. 5 is a sectional view taken on the line 55 of Fig. 4 showing thecontour of walls of Y a passageway formed between the plates of apair ofplates of the condenser and showing the locking of the pairs of platesto one'another;

Fig. -6 is a sectional view taken on the line 6-6 of Fig. 4 showingbutton-like depressions in the plates and passages which connectportions of the passageway between the plates together; and v Fig. 7 isa fragmentary sectional view taken on the line 1-1 of Fig. 4 showing thebuttonlike depressions and other contacting portions of the plates ofthe condenser.

There is shown in Fig. 1 of the drawings, a diagrammatic illustration ofa closed refrigerating system wherein a sealedmotor-conipressor curvedor arcuate portions intermediate the flat unit I 0 withdraws evaporatedrefrigerant from an evaporator ll through a conduit l2,'compresses theevaporated refrigerant and forwards the compressed fluid to a heat.exchanger or condenser, constructed in accordance with our invention andgenerally represented by the reference character It, by way of a conduitl5. Air flowing over or caused to be circulated through condenser I 4cools the compressed refrigerating fluid and liquefles the same. Thecondensed liquefied refrigerant collects in the lower portion ofcondenser H and is directed by a pipe I 6, to;

the evaporator H. A suitable restrictor or restricting device 11 may beemployed for controlling the amount of liquid refrigerant entering theevaporator. Starting and stopping of the motor and consequently thecompressor of the motor-compressor unit III, is controlled in responseto the refrigerating effect produced by the evaporator. Thus, athermostat bulb I9 is provided in heat exchange relationship with theevaporator and this bulb is connected with an expansible andcontractible bellows 2| of a snapacting switch 22, by a pipe 23. Switch22 controls the opening and closing of contacts inter posed in anelectric circuit leading to the unit In. Operation of themotor-compressor unit It under ordinary demands of refrigeration of therefrigerating system subjects the condenser to normal internal pressuresand abnormal demands of refrigeration by the refrigerating system oroperation of the system during abnor- -mal1y high temperatures causesthe interior of the condenser to be subjected to relatively highpressures. The condenser I4 is constructed substantially in its entiretyof sheet metal plates to obtain relatively flat wide refrigerantcondensing passageways and these plates are as thin as possible toreduce manufacturing costs of the condenser. Thus, the 'platesmust befabricated 38 are located at the center of four of the dimples toprovide strong walls for the refrigerant passageways in order towithstand high internal pressures which frequently occur in a closedrefrigerating system.

The condenser 14 is of a box-like form and is pairs of secured togetherthin metal members or plates. {The plates of each of the plurality ofpairs thereof are fabricated or recessed to provide dimples '21 (seeFigs. 2 and 4) over substancomposed of a plurality of long relativelynarrow tiallytheir entire surface. area. The plates are all recessed inthe same direction and one plate 28 is reversely placed against anotherplate 29 to form two-plate airs and these pairs of plates are disposedone against another to provide a condenser structure or heat exchangerof the desired length. One plate 28 of each pair thereof is slightlylarger than the other plate 28 of the pair and has its peripheral edgeportions 3| bent over the peripheral edges 32 of plate 29. Each plate 28and 28, of the pairs of plates, is provided with an aperture thereinadjacent each end thereof. The walls 33 of the apertures in plates 28are flanged inwardly of the pairs and the walls 34 of the apertures inplates 28 are flanged out- 21 to thus provide the narrow communicativepassages 38 between the wider portions of the closed passageway formedby spaced apart flat portions 38 of the dimples. The spaced apart flatportions 36 of one plate 28 of a pair of plates 28 and 28 engages orabuts the corresponding spaced apart flat portions 38 of the adjacentplate 23 of another pair of plates. The portions ll of the dimples 21provide continuously curved or arcuate wall surfaces for the passagewaybetween the plates 28 and 28 and, between the secured to- I gatherpoints 31 and 38 of the plates and the space between the dimpleddepressions 21. of the pairs of plates, form a plurality of air passages48 extending transversely through the heat exchanger. It will be notedthat a relatively flat wide confined fluid passageway is providedbetween the plates 28 and 29 of each pair thereof and that the securingof walls 33 and 34 of the apertures in the plates provide spaced apartheaders extending along the, length of the exchanger and communicatingwith each of the closed fluid passageways. The continuously curved oropposedconvex wall surfaces ll for the fluid passageway between theplates of'each pair of plates affords a wall structure for thepassageway which is of increased strength ,and capable of ,with'-standing high pressures. This increased strength is obtained by forminall portions of the walls of the passageways, except the abutting orsecured together portions thereof, with a continuously curved surface ora' surface that is curved in a direction opposite the direction ofapplication of internal pressure thereto. The abutting flat points orportions 36 of the pairs of plates diswardly. The walls 34 of thapertures in plates 23 telescope or fit into'the walls 33 of theapertures in plates 28 (see Fig. 5) and have their edge por tions bentor spun over and secured to theedge portion of the walls 33 to lock thepairs ofplates together. The depressions or dimples 21 in plates 28 andinclude spaced apart flat portions 38 and intermediate continuouslycurved orarcuate portions 4|. ,The depressions or dimples 21 areoppositely disposed when the plates 28 and 28 are secured together toprovide the pairs of plates- Plates 28 and :s have contacting wallportions 31 (see Figs. 5' and 6). Spaced apart portions of plates 28 and29 form a relatively flat wide fluid passageway between the plates ofeach pair thereof and the curved or arcuate portions 4| provide spacedapart opposedconvex wall surfaces for the passageway. The contactingportions 31 of each pair of the plates 28 and-28 are deformed one intotthe other to provide a plurality ofsmall roundinterflttin'g button-likedepressions 38 (see Figs. 8

and '1) which provide a mechanical connectiill tribute pressure withinany one passageway to other pairs of plates. Thus, the wall surfaces lland contacting flat points 36 cooperate with one another to provideincreased structural strength of the thin plates of the condenser. Arelatively heavy plate 42 having a mounting bracket 43 thereon issecured to each end plate of the heat exchanger or condenser 14. One endof each of the headers within the condenser structure I is I closed by aplug H (see Fig; 2) and the other end of each header is provided with asuitable elbow pipe 88 to form a fluid inlet and a fluid outlet for thecondenser Id. The plates 28 and 28 of condenser may be individuallyassembled together with the proper bending of their edges and spinningof walls of the apertures therein and thereafter the structure may beplaced in a brazing furnace with a suitable spelter and bonding materiallocated within the passageways and headers of the assembled condenser.The structure will. upon being heated in the furnace, cause, bondingtogether of contiguous portions of the metal plates 28 and fl. brazingof the plates together is conventional and well known to those skilledin the art and it is to be understood that the end plates 42, plugs 44and elbow pipe connecting means 88 may be braced to theplates atthe'same time the plates are-brazed to one another.

Metal members or plates '28 and 20 are ap-. proximately .012 inch inthickness and the pre- Iabflcatlon thereof with the plurality of dimple-S'uch assembling and metal walls of such thickness.

like depressions I! greatly increases thestructural strength of walls ofpassageways between the plates over that ordinarily obtainable from ofthe thin metal as described and their being secured together at theiredges and at a plurality of points intermediate their edges and adjacentthe dimples 21 prevent the plates from buckling or bulging upon theoccurrence of high pressure within the .structure. Abutment of the flatportions 36, of dimples 21 of the plates of one pair of plates, with thecorresponding flat portions 36 of dimples 21 of the plates of otherpairs of plates, increases the structural strength of the structure inthat internal pressure is distributed at a plurality of points and overa wide area to prevent spreading apart of the pairs of plates.

By this construction and arrangement thesecured together wall portions33 and 34 of the apertures in the plates function or serve to form thesole means of locking the pairs of plates of the structure together. Thenecessity of providing additional tying means across the length of thestructure either internally or exterior] thereof is eliminated.

By fabricating the metal at the contacting points 31 of plates 23 and 29to form the button- The fabrication over large areas and preventbuckling and bulging of the walls of the fluid passageways to therebyaflord a structure of increased or improved structural strength.

While the form of embodiment of the invention as herein disclosed,constitutes a preferred form, it is to'be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows: 1. A heat exchanger comprising a bank ofpairs of plates, each plate being formed with dimplelike depressionsarranged in mutually substantially perpendicular series of rows, the twoplates of each pair having their dimple-like depressions in opposedrelationship and being spaced apart throughout said rows to provide afluid passageway between the two plates, the plates of each pair beingsecured together at theiredges and at points forming rows alternatingwith the first.

mentioned rows, said depressions having fiat base portions andinteriorly convexly curved side portions, the flat base portions of thedepreslike depressions 38, we provide a small irregular contiguoussurface at the abutting points between the plates of each pair thereofand these surfaces, when bonded together, are strong and 'notllkely tobe separated by pressure within the closed fluid passageway between theplates.

.From the foregoing, it will be seen that we have provided an improvedheat exchanger and par-- ticularly a-condenser for a refrigeratingsystem which is made' substantially in its entirety of thin sheet metalplates. The condenser is of low manufacturing costs and'highly efllcientsince the refrigerant cooling and condensing passagesionsof one pair ofplates abutting corresponding flat base portions of the depressions ofadjae like depressions arranged in mutually 'substantially'perpendicularseries of rows, the two plates of each pair having their dimple-likedepressions in opposed. relationshipand being spaced apart ways are flatand wide to spread the refrigerating fluid over a large area and toexpose both.

sides of the spread-out-refrlgerant fluid to air flowing through orcirculated over tlie condenser. The thin metal sheets with which thecondenser is constructed can be readily punched and fabricated andthereafter brazed-together in plurality of interconnected closedfluidpassageways. Our improved condenser is compact and eflicient inthat it aflords the maximum of heat transfer surface within a given areaand provides for. an eii'ective flow of air overthe-fluid passagewaysthereof. Contacting portions of the plates of the condenser rapidlytransfer heat from one portion to another portion thereof to dissipatethe heat to the atmosphere and thereby throughout said rows to provide afluid passageway between the two plates, the plates of each pair beingsecured together at their edges and having nested portions diagonallybetween the a bank comprising pairs of the sheets to form the dimples ofadjacent rows, each of said depressions having a flat base portion andan interiorly convexly continuously curved side portion, the

flat base portions of the depressions of one pair of plates abuttingcorresponding flat base portions of the depressions of adjacent pairsofplates, the dimple-like depressions in said rows in each plate beingcontiguous to one another and the curved side portions of thedepressions in each pair of plates. thereby providing opposed interiorlyconvex wall surfaces for said fluid pasreduce the temperature gradientbetween portions of the condenser. The contacting portions of the platestogether with the continuously curved wall portions of the dimplesadjacent the con- 'W portions thereofdivide internal pressures sagewaycontinuously along said rows between the wall surfacesthereof providedby the flat base portions of the opposed spaced apart dimplelikedepressions in each pair of plates.

ANDREW A. sun: A. McCORMACK. Ginsu w. wonco'rr.

